Pope John Paul II has ended a grueling four-day tour in Slovakia that included the beatification of two clerics who were persecuted by the country's former communist regime.

An estimated 200,000 pilgrims sang and prayed at an emotional mass in the Slovak capital, Bratislava, where an ailing John Paul beatified a Slovak bishop and a nun considered by the Catholic Church to be martyrs of the recent communist era.

Dressed in bright red and gold vestments, the pope officiated at a mass against a backdrop of drab soviet-style housing units, which church officials described as a "city built without God."

Many in the congregation said they feared this was likely to be the pope's last visit to the region, considering the frail health of the pope, who suffers from Parkinson's disease and finds it difficult to walk.

But the pope's frailty also served as an inspiration to many, including the sick. In the words of Slovak Bishop Rudolf Balaz, his visit was precious because he came with "such strain and bearing a cross."

Suffering was a theme at his sermon Sunday, when the 83-year old Polish-born pontiff beatified nun Zdenka Schelingova and Bishop Basil Hopko - Slovaks persecuted by communists in the 1950s, when Slovakia was still part of former Czechoslovakia.

Bishop Hopko was tortured before being tried and convicted of "subversive activities" and contacts with a "foreign power" because of his ties to the Vatican.

Sister Zdenka was tortured and imprisoned for helping persecuted priests escape communism. She was released for medical reasons after three years imprisonment, but died several weeks later.

The pope said the world could be inspired by their faith and perseverance.

He said that "both shine before us as radiant examples of faithfulness in times of harsh and ruthless religious persecution..." And the pontiff added that "both faced up to an unjust trial and an ignoble condemnation, to torture, humiliation, solitude, death."

In recent days the pope also urged the mainly Catholic Slovaks to use their post-communist freedom wisely, at a time when the Vatican is concerned about a parliamentary decision to allow abortions up to 24 weeks of pregnancy.

As the pope left Slovakia, many of his followers wondered if the frail John Paul can continue his travels. His papacy, 25 years long next month, has been marked by his globetrotting.

He has visited more than 130 countries on 102 trips, traveling an estimated 1.5 million kilometers - equivalent to going round the world about 30 times.